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Halogen Bulb Problem

Mike Temple

New Member
When I replace a 20w, 12v, G4 bulb in an accent light in a cabinet with a 10w, 12v, G4 bulb it just flashes once and goes out when I turn it on. The 20W bulb works fine but I have tried 2 different manufactures 10w bulbs and they do the same thing. The don't burn out since the flash once each time I turn them on. Is ther an internal thermal breaker in the bulb. Could the voltage be too high? Any comment would be appreciated.
 

proffski

New Member
When I replace a 20w, 12v, G4 bulb in an accent light in a cabinet with a 10w, 12v, G4 bulb it just flashes once and goes out when I turn it on. The 20W bulb works fine but I have tried 2 different manufactures 10w bulbs and they do the same thing. The don't burn out since the flash once each time I turn them on. Is ther an internal thermal breaker in the bulb. Could the voltage be too high? Any comment would be appreciated.
Surprisingly some electronic transformers (I assume that is what you are using) need a minimum load to operate correctly. If the transformer is easy to access check any print on it and see as to what it says.
See here: http://images.maplin.co.uk/full/nl50e.jpg

It clearly states a minimum and maximum load rating...

Andy.
 

Mike Temple

New Member
I am sure there is a transformer - unfortunately it is mounted on top of the built in cabinet and is totally inaccessable. I guess I am stuck with a 20w light. I'll find another means of toning it down. Thanks for the help. :)
 

tunedwolf

Well-Known Member
Wire two 10W lamps in parallel and isolate one of the transformer outputs.
Pretty much all of these small switching lighting transformers operate with a 20W min load and a 60W max load. The bigger ones are 50W to 105W or 50W to 205W depending on model. I haven't seen any larger than that used for halogen lighting, usually beyond that real transformers are used.

rgds
 

Hero999

Banned
Care to enlighten us?

Did you ad a resistor in parallel?
 

Mike Temple

New Member
Thanks for all the good ideas and advice.
My real problem was not so much a bulb problem but a "too bright a light" shining from the top of a built in cabinet. The light was intended to be a down light that shined down form the top of the cabinet through several glass shelves to give an nice lighting effect. The light was flush monted to the top of the cabinet and was just too bright and in your face. Ithought that going from a 20w bulb to a 10w bulb would at least tone it down. That is when I encountered the 10w bulb doesn't work problem.

My solution was to go to Lowe's and find something that would be large enough in diameter to go around the light lens and long enough to shield the light from your face and direct it downward for the desired effect. After several hairbrainded ideas which would use a short piece of plastic pipe, I stumbled into the perfect solution. It was a "post cap" for mounting an oudoor lamp on a wooden post. It was just the right diameter and length, had mounting screw holes and was the right color. Cost me $3.00. I now have a great down light with a 20w bulb (just right) and am a hero with my wife.
 

proffski

New Member
I love adaptation Mike, in my job it is absolutely essential.
Well done, a simple elegant solution and no mucking about with soldering iron either!
 

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